Counterfeit detection using machine readable indicia

ABSTRACT

This disclosure relates to counterfeit detection and deterrence using advanced signal processing technology including steganographic embedding and digital watermarking. Digital watermark can be used on consumer products, labels, logos, hang tags, stickers and other objects to provide counterfeit detection mechanisms.

RELATED APPLICATION DATA

This application is a continuation of U.S. patent application Ser. No.15/255,083, filed Sep. 1, 2016 (issued as U.S. Pat. No. 10,065,441),which claims benefit of U.S. Provisional Application No. 62/212,948filed Sep. 1, 2015. This application is related to assignee's U.S.patent application Ser. No. 14/616,686, filed Feb. 7, 2015 (issued asU.S. Pat. No. 9,380,186 B2), Ser. No. 14/725,399, filed May 29, 2015(issued as U.S. Pat. No. 9,635,378), Ser. No. 15/072,884, filed Mar. 17,2016 (published as US 2017-0024840 A1), Ser. No. 14/588,636, filed Jan.2, 2015 (published as US 2015-0187039 A1, issued as U.S. Pat. No.9,401,001), and Ser. No. 15/137,401, filed Apr. 25, 2016 (issued as U.S.Pat. No. 9,565,335). Each of the patent documents mentioned in thisparagraph is hereby incorporated herein by reference in its entirety,including all drawings and any appendices

TECHNICAL FIELD

This disclosure relates to counterfeit detection and deterrence usingadvanced signal processing technology including steganographic embeddingand digital watermarking.

BACKGROUND AND SUMMARY

Counterfeiting is Big Business.

The numbers are staggering:

$1.7 billion—Value of seized counterfeit goods at U.S. borders in fiscal2013. See, e.g.,http://www.iacc.org/resources/about/what-is-counterfeiting.

$1.77 Trillion—Projected Value of Global Trade in Counterfeit andPirated Goods in 2015. See, e.g.,http://www.iacc.org/resources/about/statistics.

Counterfeit goods span multiple industries including everything fromconsumer goods, apparel, accessories, music, pharmaceuticals,cigarettes, to automobile and manufactured parts, toys and electronics.

One promising technology for automated counterfeit detection issteganographic encoding (or embedding). One form of steganographicencoding includes digital watermarking. Digital watermarking is aprocess for modifying physical or electronic media to embed amachine-readable code (or “auxiliary data”) into the media. The mediamay be modified such that the embedded code is obscured, yet may bedetected through an automated detection process. Most commonly, digitalwatermarking is applied to electronic or physical objects such asimages, audio signals, and video signals. However, it may also beapplied to other types of objects, including, e.g., product packaging,electronics such as circuit boards and CPUs, stickers, logos, producthang tags, line-art, software, multi-dimensional graphics models, andsurface textures of such objects.

Auxiliary data embedding systems typically have two components: anencoder (or embedder) that embeds the auxiliary signal in a host imageor object, and a decoder (or detector) that detects and reads theembedded auxiliary signal from the host image or object. The encoderembeds the auxiliary signal by altering an image or object or generatinga signal carrying the auxiliary data. The detection component analyzes asuspect image, object or signal to detect whether an auxiliary signal ispresent, and if so, extracts or reads information carried in it.

Several particular digital watermarking and related auxiliary dataembedding techniques have been developed. The reader is presumed to befamiliar with the literature in this field. Particular techniques forembedding and detecting imperceptible digital watermarks are detailed inthe assignee's patent documents including U.S. Pat. No. 6,590,996; USPublished Patent Application Nos. 20140052555 and 20150156369; U.S.patent application Ser. No. 14/725,399, filed May 29, 2015 (issued asU.S. Pat. No. 9,635,378), Ser. No. 14/724,729, filed May 28, 2015(published as 20160217547; issued as U.S. Pat. No. 9,747,656), Ser. No.15/073,483, filed Mar. 17, 2016 (issued as U.S. Pat. No. 9,754,341); andInternational Application No. PCT/US2015/44904, filed Aug. 12, 2015(published as WO 2016/025631). Each of the patent documents mentioned inthis paragraph are hereby incorporated herein by reference in itsentirety, including all drawings and any appendices.

This disclosure describes objects, methods, apparatus and systems usingembedded auxiliary signals to deter and detect counterfeited goods.Detection can be facilitated with a handheld reading device including acamera equipped smartphone (e.g., iPhone 6 or Samsung Galaxy 6) havingan illumination source such as a flash or torch.

One aspect of the disclosure teaches digital watermarking solutions foruse with so-called lenticular structures, e.g., lenticular lenses.Multiple, inter-related but different watermark payloads can be printedon the lenticular structure and viewed at differing angles. Suchlenticular structures can include or cooperate with an adhesive forapplication as a sticker or label, or for direct application on aconsumer packaged good. The multiple, different watermark payloads canbe detected along with watermark signal strength at different viewingangles. A counterfeit without a lenticular structure will not having avarying signal strength associated with different angles, and thus canbe recognized as fraudulent.

Another aspect of the disclosure teaches digital watermarking solutionsusing metallic inks. The metallic ink carries a digital watermark signalwhich can be obscured, in part, by a cooperating metameric (butnon-metallic) spot color. The metallic and cooperating spot color willappear flat or the same (e.g., not show watermark modulations) unlessilluminated by torch or detected by movement. Scanning and re-printing ametallic-ink-watermarked object will not include the same metallic inkin a reproduction, allowing for rapid and automated detection of thecounterfeit.

Still another aspect of the disclosure teaches a narrow band absorptiondye for conveying a digital watermark signal. The narrow band can beselected to cooperate with a mobile device's illumination source. Awatermark detector can read the digital watermark signal with andwithout torch illumination, and the difference in watermark strength canbe used to determine if an object is an original or counterfeit.

Yet another aspect teaches metameric ink pairs selected from, e.g.,PANTONE inks, that change their color properties as seen by a camera andcooperating watermark detector under differing illumination. A digitalwatermark signal may be detected under one lighting condition and thenreverse its signal polarity under a differing lighting condition. Thediffering signal polarities can be used to recognize an object asgenuine.

Further aspects, features and advantages will become even more apparentwith reference to the following detailed description and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawing(s) will be provided by the Office upon request and paymentof the necessary fee.

FIG. 1A illustrates lenticular printing with a lens structure and aninterlaced image.

FIG. 1B illustrates a lenticular structure having interlaced strips.

FIG. 1C illustrates a lenticular structure having interlaced watermarkedimages.

FIGS. 2A and 2B simulate images to show an effect of flash illumination(FIG. 2B) vs. ambient lighting (FIG. 2A). The circled area in FIG. 2Bshows an inverse reflection effect relative to FIG. 2A.

FIG. 3 is a diagram showing relative spectral power distribution for aniPhone 6 flash (line with a gentle bump at or around 565 nm), daylightfluorescence (line having a second narrow peak at or around 485 nm), anda narrow band dye (dashed line).

FIG. 4 illustrates color behavior in a blue channel for two differentPANTONE colors under regular office lighting (left) and flashillumination (right) for an iPhone 6.

FIG. 5 is a diagram of an electronic device (e.g., a smartphone, mobiledevice, tablet, or other electronic device).

FIG. 6A shows a target color and mixture of two inks relative to oneanother under different lighting conditions.

FIG. 6B shows color values, color errors and Euclidean distances for thedifferent grey patches of FIG. 6A.

FIG. 7 is a graph contrasting relative spectral power distribution forD50 illumination and an iPhone flash illumination.

FIG. 8 is a graph showing reflectance of various inks per wavelength.

DETAILED DESCRIPTION

The following sections describe various techniques for automaticallydistinguishing a copy from an original, among other features. Thesection headings are not meant to limit the scope of the disclosure, assubject matter under one such heading can readily be combined withsubject matter under another such heading.

I. High Capacity Lenticular Watermarking

Our first anti-counterfeiting solution combines digital watermarking andso-called “lenticular printing.”

Lenticular printing may include a process of creating a compositeinterlaced image by interlacing multiple images, and attaching orco-locating the interlaced image with a lenticular lens structure, suchas a sheet or a set of extruded lines, to form a lenticular imagearticle. See, e.g., FIG. 1A.

When digitally processing the composite interlaced image, various imagescan be collected and flattened into individual, different frame files,and then digitally combined by interlacing into a single final file.Interlacing can also involve dividing visual images into strips,alternating the image strips and arranging the image strips under afield of lenticular structures. The created image stripes from themultiple images are combined and interlaced into a single image so that,for example, a first stripe of a first image is disposed first, followedby a first stripe of a second image, followed by a second stripe of thefirst image, and so on. The interlaced images can be printed directly toa back side of the lens sheet, e.g., by a single-step process or theycan be printed to a substrate and then laminated to the lens sheet,e.g., by a two-step process, such that individual lenses of the arrayare disposed and registered over interlaced stripes. If printed onto aback side the interlaced structure, the composite image can be reverselyprinted for proper viewing from a top surface. Some common printingmethods used with lenticular structures include offset printing,flexo-printing, and printing with use of so-called “digital presses”,e.g., HP's Indigo 5600 or 7000.

Light is reflected off each stripe of a lenticular structure andrefracted through the lenses in different directions, but with lightfrom all stripes of a given image preferably refracted in the samedirection. The produced effect is that one full image (or imageportion), or a combination of all the image stripes of an originalimage, is viewable from a certain angle, and another full image (orimage portion), or a combination of all the image stripes of anotheroriginal image, is viewable from a different angle, and so on. Differenteffects can be achieved by using more or less stripes per lens and byaltering the width and height of the lenses. See e.g., FIG. 1B.

Lenticular printing, lenses, image interlacing and related printingtechniques are discussed, e.g., in U.S. Pat. Nos. 9,071,714, 9,021,947,8,854,684, 8,693,101, 8,668,137, 8,605,359, 8,416,499, 7,712,673,7,153,047, 6,900,944, 5,967,032, and 5,457,515, which are each herebyincorporated herein by reference in its entirety.

Returning to our anti-counterfeiting solution, multiple images (e.g.,3-12 images) are embedded with different digital watermarks, e.g., witheach watermark including a different plural-bit payload, perhapsembedded with different signal strengths or properties. The images candepict really anything, including a brand logo, a noise pattern, aphotograph, a design, artwork, etc.

Although different, the watermark payloads can be related in variousways. For example, only one of the plurality of payloads may be encodedwith a public key (“public payload”). The remaining payloads can beencoded with one or more private keys (“private payloads”). Once decodedwith the public key, the public payload can be used as an index toobtain, e.g., the corresponding private key(s) or the resulting expectedprivate payloads. The index can be used locally with respect to an imagecapture device or communicated to a remote repository, e.g., a cloudbased database.

A different implementation uses one or more public keys to decode eachof the watermark payloads. The payloads are associated in a database,with a majority (or super majority) of decode payloads needed forauthenticity. For example, for authentication, all decoded payloads areprovided to a remote database and a super majority of them must matchpayloads within a set of payloads in order for the object to be deemedauthentic.

In another implementation, the different payloads may be related througha cryptographic permutation. Once recovered, the different payloads canbe processed with an inverse of the permutation to see if theycorrespond in an expected manner.

In still another implementation, an original payload is processed withan erasure code generator. The code generator produces a plurality ofoutputs corresponding to the original payload. Not all of the pluralityof outputs are needed for a decoder to reconstruct the original payload,and non-sequential outputs can be used to reconstruct the originalpayload. Different outputs from the plurality of outputs are used as thedifferent watermark payloads. Related payload construction is discussedin assignee's Published US Patent Application Nos. 20150227925 and20140244514, e.g., with reference to their FIG. 16. Both of these USPatent publications are hereby incorporated herein by reference in theirentirety.

Recall from above that multiple images (e.g., 3-12 images) are embeddedwith different digital watermarks, e.g., with each digital watermarkincluding a different plural-bit payload. The multiple images, e.g.,watermarked image 1-n (n being an integer), can be combined andinterlaced into a single composite image so that, for example, a firststripe of the first watermarked image is disposed first, followed by afirst stripe of the second image, . . . , followed by a first stripe ofthe nth watermarked image, followed by a second stripe of the firstwatermarked image, and so on. See, e.g., FIG. 1C.

A mobile device, e.g. a smartphone, obtains optical scan data frommultiple different angles across the image. The optical scan datacorresponds to the different watermarked images at different angles. Awatermark detector analyzes the optical scan data to decode thedifferent watermark payloads at the different angles. (Changing heightor scale of the smartphone while capturing images may also yielddifferent views.)

In addition to decoding the different payloads, the watermark detectorcan also determine a watermark “signal strength” or strength metric foreach of the watermarks.

In one implementation, the digital watermark includes two primarycomponents: a payload and a calibration signal. The calibration signalpreferably remains the same from watermark to watermark. In one example,the calibration signal includes a constellation of peaks and associatedphase in a transform domain. The watermark payloads may vary fromwatermark to watermark, of course, to carry different information. Ifthe calibration signal is the same from watermark to watermark, and thepayload is the changing signal, then a correlation with a payload tilemay yield a signal strength. This correlation may be between a filteredimage and array of watermark payload tweaks across the watermarkedimages.

Additional signal strength metrics are discussed in U.S. Pat. No.7,054,461, e.g., a so-called Power Ratio and Payload RecoveryAssessment. The U.S. Pat. No. 7,054,461 is hereby incorporated herein byreference in its entirety.

The power ratio metric measures, e.g., the degradation of a watermarksignal (e.g., a calibration signal) at selected frequencies.

The payload recovery assessment measures watermark strength, includingthe degree of correlation between a reference signal and a detectedsignal, and a measure of symbol errors in raw message estimates. One wayto measure the symbol errors is to reconstruct the raw message sequenceusing the same error correction coding process of the embedder on thevalid message extracted from the watermark. This process yields, forexample, a string of 1000 binary symbols, which can be compared with thebinary symbols estimated at the output of a spread spectrum demodulator.The stronger the agreement between the reconstructed and detectedmessage, the stronger the watermark signal.

Additional signal strength metrics are found, e.g., in the '461 patentand U.S. Pat. No. 7,286,685, which is hereby incorporated herein byreference in its entirety. See also the detection measures, signalstrength and other metrics discussed in assignee's U.S. patentapplication Ser. No. 15/154,529, filed May 13, 2016, which is herebyincorporated herein by reference in its entirety.

Once a signal strength (or detection measure) is determined for aparticular watermark, it too can be used as an authentication clue. Forexample, it is possible that multiple digital watermarks may bedetectable from a first viewing angle. How, the digital watermarks inthe different images can be arranged so as to have different signalstrengths (or detection measures). So an authentic detection may includea combination of expected payload reads with varying signal strengthsacross the lenticular structure.

A signature corresponding to signal strength or detection measure, or asignature corresponding to signal strength plus watermark payloads, canbe used to authenticate, e.g., a consumer product, including awatermarked lenticular structure. The signature may include a ratio orrelationship of signal strength across the lenticular structure. Thesignature may alternatively include an x amount (where x is an integeror percentage) of successfully decoded payloads, along with some measurequantifying variation in signal strength between the successfullydecoded watermarks.

The signature may also rely on information from a device gyroscope. Forexample, angle and or position information may be obtained from thegyroscope and associated with each successful read. In a simpleimplementation, the lenticular lens structure is validated when eachsuccessful read had a different device position/angle as obtained fromthe device's gyroscope. In more complex implementations, relativeposition/angle differences between successful reads are compared againstexpected differences to ensure validation. The differences may beobtained from one or more of the different watermark payloads, oraccessed in a remote repository. In some cases, the device gathersdevice position, signal strength and watermark payload information andsends such (or an abbreviated or filtered version of such) to a remoterepository, which houses expected signature values.

Thus, the signature may be validated locally on a smartphone or othermobile device, or underlining information for such a signature may beprovided to a remote location for validation.

The portable device may also include a graphical user interface (GUI),e.g., generated by a software program or app and displayed on a touchscreen. The GUI may provide instructions or graphical prompting during avalidation process. For example, an overlaid graphical box may outlinethe lenticular structure, with arrows directing relative motion betweenthe device (camera view) and structure. The box can be shaded (oroverlaid with different colors, green=success, red=keep trying) once asuccessful read is determined at a corresponding viewing angle. Inanother example, the GUI provides an arrow, bar or heat map to guide theuser in scanning a watermark embedded lenticular structure. In stillanother implementation, the GUI provides a graphic of a ball or otherobject, which the user controls by relative movement of the device tothe lenticular structure. In a game-like fashion the user must coverenough viewing angles to ensure that some or all of the payloads aredetected. Input from a device gyroscope/accelerometer can be used toprovide feedback and ball tracking.

One suitable lenticular material is Dura-Go/Lenstar Lenticular having101.5 LPI (Lines per inch), 14 mil (350 micron) made by Tekra, adivision of EIS, Inc. The Dura-Go is designed for use with the HP Indigo5600 press. It has 101.5 lenticules per inch parallel to the 12 inchside of the sheet, and allows for reverse printing on the lenticularsheet.

Another suitable lenticular material is Forward Optics's MicroFlex LensArray with 310 Lenses per inch (122 lenses per cm). Related lensstructures can be found in U.S. Pat. No. 6,856,462, which is herebyincorporated by reference in its entirety.

In some implementations, one or more of the plural watermark payloadsincludes or cooperates with a serialization code. The serialization codeprovides a unique code with can be uniquely associated with a consumer,a product, a lot number, a distributor, etc. In these cases theserialization code includes a unique number that is associated with aconsumer, retailer or distributor once the product is sold orregistered. The association between the serialization code and consumer,retailer or distributor can be maintained, e.g., in a cloud-based datastructure. Serialization can be readily facilitated by printing on adigital press, e.g., HP's Indigo presses. The serialization code can bechanged per lenticular structure, batch of structures, etc.

In a brief, non-exhaustive summary, lenticular printing renders, e.g.,3-12, different images depending on relative camera pose/angle. Thedifferent images may each include a different digital watermark payload.The multiple different watermark payloads can be read at a determinedsignal strength that is associated to camera angle/pose or associatedwith an expected pattern or relationship across a lenticular structure.A counterfeit without a lenticular lens will not vary signal strengthbased on pose and thus can be recognized as fraudulent. Additionally, acounterfeit is unlikely to include all watermark payloads in a singleimage.

II. Anti-Counterfeit Signaling Using Metallic Inks

Our second solution utilizes machine readable indicia printed withmetallic inks. Machine readable indicia may be carried by an encodedsignal, e.g., digital watermarking. One example of digital watermarkingis a continuous or sparse signal (“sparse mark”) as disclosed inassignee's U.S. patent application Ser. No. 14/725,399 (issued as U.S.Pat. No. 9,635,378) and Ser. No. 15/072,884 (published as US2017-0024840 A1), which are each hereby incorporated herein by referencein their entirety. Metallic inks (e.g., PANTONE PREMIUM Silver andPANTONE 877 Silver) are highly reflective when illuminated with a lightsource, e.g., a smartphone's flash or torch, compared to traditionalinks. Metallic and regular ink of a similar color will appear flat orthe same when printed unless illuminated by a torch or viewed at aparticular diffuse reflection angle. With illumination, the metallic inkwill have a higher reflectance compared to the regular ink. Ananti-counterfeit digital watermark can be carried by the metallic ink. Alarge pallet of metallic colors is available in the PANTONE system forselection.

Metallic ink can be used to provide a so-called “sparse mark.” Thesparse mark becomes detectable under illumination with a torch. Forexample, the metal particles strongly reflects light relative to theregular ink. For a sparse mark, the signaling phase can be inverted sothat highly reflective area correspond to the dark areas, e.g., as showin FIGS. 9-12 of the Ser. No. 14/725,399 application (and as issued inU.S. Pat. No. 9,635,378). The metallic ink can overprint the regular inkso that it appears flat with the regular ink under normal lightingconditions, but highly reflects with a flash.

One authentication process obtains two (2) optically captured images(e.g., captured by a smartphone, digital camera, point of sale scanner,etc.) representing a metallic-ink-watermarked image, the first capturewith a flash, and the second capture without a flash. Most often, thewatermark will not be readable without the flash. For example, and withreference to FIGS. 2A and 2B below, a metallic ink can have a strongreflectance under illumination (FIG. 2B) compared to ambient lighting(FIG. 2A). See the circled area in FIG. 2B, and compare that area to thecorresponding area in FIG. 2A.

In some cases, however, the watermark may be detectable at a certaindiffuse reflection angle. In these cases, however, the digital watermarksignal should be noticeably stronger (e.g., in terms of signal strength)with the flash than without. Suitable signal strength metrics arediscussed above under Section I. For authentication and counterfeitdetection, a watermark signal strength for each the two images (flashand no flash) is determined and then used for validation, since therewill be a relatively stronger signal strength associated with theflashed image.

A counterfeited copy may include the watermark signal, but should nothave such a relatively different signal strength (or change in messagecarrier polarity) between an image captured with a flash and onecaptured without. Additionally, two or more images can be capturedwithout the flash, with at least one being captured at a viewing anglewhich obtains some diffuse reflection of the metallic ink. Signalstrength of these two images can be used to determine an original(differing signal strength between the two images) from a counterfeit(negligible signal strength different between the two images).

Serialization on a digital press can be achieved by printing withsilver/gray ink or printing with opaque white and gray on top of asilver foil. In the latter case, the white or gray covers all foilareas, e.g., except where a digital watermark is to be placed.

III. Narrow Band Absorption Dye

We have found that a wide variety of smartphones include an illuminationtorch having a non-uniform spectral distribution with a peak at oraround 450 nm, and low power at or around 475 nm. This torchillumination is different from typical broadband ambient illumination(e.g., see “iPhone 6” vs. “Daylight Fluorescent” illumination shown inFIG. 3). We use the terms “at or around” in this patent document to meanplus or minus 15 nm. So, “at or around 450 nm” includes a range of 435nm-465 nm, and “at or around 475 nm includes a range of 460 nm-490 nm.

A narrow band dye with a notch or minimum centered on or around thevalley of the torch illumination produces a reflectivity change when thetorch is switched on and off. See the dashed line in FIG. 4 for therelative spectral power distribution of the narrow band dye. Printing awatermark with a dye that has narrow band absorption at or around 475 nmyields a yellowish pattern. The contrast of the yellow pattern isreduced with torch illumination compared to ambient illumination. Forexample, see the Table 1, below, showing a simulation of a yellowpattern tint with ambient vs. torch illumination. Table 1 also shows anotch or minimum centered at or around 445 nm. As can be seen in thetable, a center notch at or around 475 produces greater reflectiondifferences.

TABLE 1 Blue Channel Change with Original (Narrow Band Dye) AndroidTorch - Daylight - Dye Type Blue Reflection Blue Reflection 475 nm(centered) 98% 87% 445 nm (centered) 82% 87%

Due to the lower reflectivity with the daylight illumination, a scannerwill likely see more of a digital watermark signal under daylight vs.torch illumination. Hence detected watermark signal strength will likelybe stronger with the ambient light detection relative to the torchillumination.

A digital watermark signal can be printed with the narrow band dye witha notch or minimum centered at or around 475 nm. The dye can be added toa varnish layer and used to print a digital watermark pattern on anoffset or flexo press. Alternatively, the dye could be coated onto apackage substrate and an opaque ink could then be used to cover up allbut a digital watermark pattern, e.g., like a sparse mark discussedabove. See also assignee's U.S. patent application Ser. No. 15/073,483,filed Mar. 17, 2016 (issued as U.S. Pat. No. 9,754,341), which is herebyincorporated herein by reference in its entirety, for an additionaldiscussion on signal encoding with narrow band dyes and pigments, etc.

The dye with which this watermark signal is printed desirably appearsclear on a substrate like a product package or sticker, to humaninspection.

The width of the notch will depend on the range of illumination that isexpected to be encountered. Desirably the notch is 100 or lessnanometers in width. The illustrative embodiment has a notch of lessthan 50 nm in width. Other embodiments may have notches of less than 40nm, e.g., 30, 20 nm or 10 nm. (Width is here measured as the bandwidthat which 50% or more of the incident light is absorbed.)

Inks and narrow band absorption dyes suitable for this spectral-notchingpurpose are available from a variety of suppliers, including StardustMaterials, LLC (Vancouver, Wash.), Gans Ink and Supply Co. (Portland,Oreg.), QCR Solutions, Corp. (Port St. Lucie, Fla., e.g., productVIS637A), Gentex Corp (Carbondale, Pa.) and SICPA SA (Lausanne,Switzerland). Some of the vendors make products to order, in accordancewith specified customer requirements. Narrow-band absorbent dyes arealso detailed in various patent documents, including U.S. Pat. Nos.5,998,609, 7,559,983, 7,892,338, 8,840,029, 20120065313, and EP0638614.Such dyes can be carried by a gloss or matte varnish, such as Gans partnumber #26240.

For counterfeit detection, a detector would expect to see a differencein detected watermark signal strength under ambient and flashillumination. The signal strength metrics discussed above under SectionI can be suitably used as metrics for these applications. Onceauthentication process proceeds as follows:

Switch on torch and read digital watermark from blue channel, anddetermine a corresponding signal strength=>signal strength 1.

Switch off torch and read watermark from blue channel, and determine acorresponding signal strength=>signal strength 2.

If signal strength 2 is greater than signal strength 1 then the documentis considered an original. “Greater” is a relative term that can be setwith testing of a particular dye and particular torches, and by thenestablishing relative thresholds.

A counterfeit would have approximately the same signal strength for awatermark signal detected from an image using torch illumination andwith ambient lighting. The color in a counterfeit will likely bereproduced by a light yellow tint which has a broad absorption curve,since the typical ink jet printer would not have access to the narrowband dye. Table 2 shows a simulation of a yellow pattern tint(counterfeit) with ambient vs. torch illumination.

TABLE 2 Blue Channel Change with Counterfeit (Wide Band Dye) AndroidTorch - Daylight - Dye Type Blue Reflection Blue Reflection Light yellow88% 88%

A software program running on the smartphone (or other portable device)may include a graphical user interface which signals to user that theitem is genuine or a fake. Such a determination can be based on awatermark signal strength comparison as discussed above.

IV. Single Channel Metamers using Spot Colors

Another anti-counterfeiting technique uses cooperating spot color inks,e.g., PANTONE inks, that change color properties as seen by an imagesensor and digital watermark detector based on different illuminationconditions.

For example, consider FIG. 4. Pantone 2240 U and Pantone Rhodamine areselected a cooperating pair. A digital watermark is printed on an objectusing positive and negative signal modulations (e.g., tweaks) conveyedwith the 2240 U (e.g., used for a negative tweak) and Rhodamine (e.g.,used for a positive tweak). The tweaks can be arranged in a pattern,e.g., according to a spread spectrum function or sparse mark pattern, toconvey a digital watermark signal. Under ordinary office lightingconditions a smart phone (e.g., iPhone 6) captures image data andanalyzes the data in a sRGB space.

The blue channel of captured image data can be analyzed to detect thetweak values. Under ordinary lighting conditions the blue channelRhodamine tweaks are relatively darker than the 2240 U tweaks. Underflash illumination, however, the Rhodamine tweaks appear relativelylighter compared to the 2240 U tweaks. This would, in effect, invert thepolarity of digital watermark signal. A digital watermark detector canbe configured to interpret both polarities to detect the same watermarkpayload.

Thus, a digital watermark signal detected under one lighting source(e.g., ambient) may reverse its polarity under a different lightingsource (e.g., flash illumination) and therefore be recognized asgenuine. A detector can be specifically configured to expect differingpolarities with different image captures. If the inverted polarities arenot found, the object is considered a fake.

Now consider a copy of an object printed using the Rhodamine and 2240 Utweaks. Since these original colors are unique “spot colors” anyreproduction (e.g., using an ink jet printer) will likely use processcolors, e.g., CMYK. Process color inks are designed to have a stablecolor response across different lighting conditions and will thereforenot yield an inverted polarity under flash illumination. Thus, acounterfeit can be recognized by taking two images of an object, oneunder ambient conditions and one under flash illumination. The two imagewill have the same polarity in a counterfeit.

V. Metallic Inks and Ink Pairs

Additional robustness can be achieved by combining two approaches, e.g.,using metallic ink and ink pairs.

For example, when creating an encoded signal on a printed object (e.g.,product packaging), we can use a metallic ink plus an ink pair. Consideran example of PANTONE metallic 877 C, and a mix of PANTONE 804 C andPANTONE Process Blue (PB) C. With reference to FIG. 6A, a target color,PANTONE 877 C is selected for inclusion in a design. An ink pair, Ink 1and Ink 2, are then selected such that a mixture of the two colors,approximates the target color under a first illumination source.Approximates in this specification refers to a color error between themix and target color is equal or lower than 1 JND or a color error (ΔE)of 1 or lower. In this example, a mix of 56% 804 C and 44% Process BlueC can be used. The Ink 1 and Ink 2 mix approximates the target colorunder D50 (e.g., daylight) illumination as seen in FIG. 6A. In fact,with reference to FIG. 6B, the CIELAB values and the sRGB (more similarto a machine vision) for the 804 C/Process Blue C mix and the PANTONE877 C, under D50 illumination, are the same.

These two colors (877 C and mix) have a very different appearance underflash illumination. In fact, with reference to FIG. 6B, the CIELABvalues and the sRGB (more similar to a machine vision) result in a ΔE ofapproximately 4 and a Euclidean distance of around 13 under iPhone 6illumination.

One outcome of this combination is that the two patches appear to be thesame shade of gray (ΔE ˜0.5) under one viewing condition (daylight D50),yet appear to be visually different (ΔE ˜4) under a second illumination(iPhone torch).

The relative spectral power distribution per wavelength for D50 and aniPhone 6 torch is shown in FIG. 7. A reflectance per wavelength chart isshown in FIG. 8, where PANTONE 877 C, Process Blue (PB) C, 804 C and amix of 804 C and PB C are shown. As shown, the set of inks can create aneutral, but the combined spectrum of the mix is much different than themetallic. In practice, it's optimal to have the largest difference occurat the same locations as the largest difference between theilluminations. In this example, D50 and the torch have a largedifference at or around 480 nm and 700 nm. As mentioned above, we usethe terms “at or around” in this patent document to mean plus or minus15 nm. So, “at or around 480 nm” includes a range of 465 nm-495 nm, and“at or around 700 nm includes a range of 685 nm-715 nm.

Such a combination of colors is a good anti-counterfeiting measure sinceinkjet printers can't recreate this effect, since consumer inks aretypically limited to CMYK and are not expected to change their spectralproperties in such a dramatic fashion.

So a sparse mark (or other encoded signal) could be detectable under aflash illumination (e.g., iPhone 6) since the grey patches (e.g., 877Cand mix) are visually different, but are not distinguishable undernormal lighting conditions since the grey patch approximate one another.

VI. Operating Environment

The components and operations of a watermark encoder (or embedder) anddecoder (or detector) can be implemented in modules. Notwithstanding anyspecific discussion of the embodiments set forth herein, the term“module” may refer to software, firmware or circuitry configured toperform any of the methods, processes, functions or operations describedherein. Software may be embodied as a software package, code,instructions, instruction sets or data recorded on non-transitorycomputer readable storage mediums. Software instructions forimplementing the detailed functionality can be authored by artisanswithout undue experimentation from the descriptions provided herein,e.g., written in C, C++, MatLab, Visual Basic, Java, Python, Tcl, Perl,Scheme, Ruby, and assembled in executable binary files, etc., inconjunction with associated data. Firmware may be embodied as code,instructions or instruction sets or data that are hard-coded (e.g.,nonvolatile) in memory devices. As used herein, the term “circuitry” mayinclude, for example, singly or in any combination, hardwired circuitry,programmable circuitry such as one or more computer processorscomprising one or more individual instruction processing cores, parallelprocessors, state machine circuitry, or firmware that storesinstructions executed by programmable circuitry.

Applicant's work also includes taking the scientific principles andnatural laws on which the present technology rests, and tying them downin particularly defined implementations. One such implementation iselectronic circuitry that has been custom-designed and manufactured toperform some or all of the component acts, as an application specificintegrated circuit (ASIC).

To realize such an implementation, some or all of the technology isfirst implemented using a general purpose computer, using software suchas MatLab (from Mathworks, Inc.). A tool such as HDLCoder (alsoavailable from MathWorks) is next employed to convert the MatLab modelto VHDL (an IEEE standard, and doubtless the most common hardware designlanguage). The VHDL output is then applied to a hardware synthesisprogram, such as Design Compiler by Synopsis, HDL Designer by MentorGraphics, or Encounter RTL Compiler by Cadence Design Systems. Thehardware synthesis program provides output data specifying a particulararray of electronic logic gates that will realize the technology inhardware form, as a special-purpose machine dedicated to such purpose.This output data is then provided to a semiconductor fabricationcontractor, which uses it to produce the customized silicon part.(Suitable contractors include TSMC, Global Foundries, and ONSemiconductors.)

Another specific implementation of the present disclosure includeswatermark detection operating on a specifically configured smartphone(e.g., iPhone 6 or Android device) or other mobile device, such phone ordevice including a flash or torch. The smartphone or mobile device maybe configured and controlled by software (e.g., an App or operatingsystem) resident on the smartphone device. The resident software mayinclude a digital watermark detector and signal strength metricgenerator.

For the sake of further illustration, FIG. 5 is a diagram of anelectronic device (e.g., a smartphone, mobile device, tablet, or otherelectronic device) in which the components of the above encoder and/ordecoder embodiments may be implemented. It is not intended to belimiting, as the embodiments may be implemented in other devicearchitectures or electronic circuitry.

Referring to FIG. 5, a system for an electronic device includes bus 100,to which many devices, modules, etc., (each of which may be genericallyreferred as a “component”) are communicatively coupled. The bus 100 maycombine the functionality of a direct memory access (DMA) bus and aprogrammed input/output (PIO) bus. In other words, the bus 100 mayfacilitate both DMA transfers and direct CPU read and writeinstructions. In one embodiment, the bus 100 is one of the AdvancedMicrocontroller Bus Architecture (AMBA) compliant data buses. AlthoughFIG. 5 illustrates an embodiment in which all components arecommunicatively coupled to the bus 100, it will be appreciated that oneor more sub-sets of the components may be communicatively coupled to aseparate bus in any suitable or beneficial manner, and that anycomponent may be communicatively coupled to two or more buses in anysuitable or beneficial manner. Although not illustrated, the electronicdevice can optionally include one or more bus controllers (e.g., a DMAcontroller, an I2C bus controller, or the like or any combinationthereof), through which data can be routed between certain of thecomponents.

The electronic device also includes a CPU 102. The CPU 102 may be anymicroprocessor, multi-core microprocessor, parallel processors, mobileapplication processor, etc., known in the art (e.g., a ReducedInstruction Set Computer (RISC) from ARM Limited, the Krait CPUproduct-family, any X86-based microprocessor available from the IntelCorporation including those in the Pentium, Xeon, Itanium, Celeron,Atom, Core i-series product families, etc.). Another CPU example is anApple A8 or A7. The A8 is built on a 64-bit architecture, includes amotion co-processor and is manufactured on a 20 nm process. The CPU 102runs an operating system of the electronic device, runs applicationprograms (e.g., mobile apps such as those available through applicationdistribution platforms such as the Apple App Store, Google Play, etc.,or custom designed to include watermark detection and objectauthentication) and, optionally, manages the various functions of theelectronic device. The CPU 102 may include or be coupled to a read-onlymemory (ROM) (not shown), which may hold an operating system (e.g., a“high-level” operating system, a “real-time” operating system, a mobileoperating system, or the like or any combination thereof) or otherdevice firmware that runs on the electronic device. Watermark detectioncapabilities can be integrated into the operating system itself.

The electronic device may also include a volatile memory 104electrically coupled to bus 100. The volatile memory 104 may include,for example, any type of random access memory (RAM). Although not shown,the electronic device may further include a memory controller thatcontrols the flow of data to and from the volatile memory 104.

The electronic device may also include a storage memory 106 connected tothe bus. The storage memory 106 typically includes one or morenon-volatile semiconductor memory devices such as ROM, EPROM and EEPROM,NOR or NAND flash memory, or the like or any combination thereof, andmay also include any kind of electronic storage device, such as, forexample, magnetic or optical disks. In embodiments of the presentinvention, the storage memory 106 is used to store one or more items ofsoftware. Software can include system software, application software,middleware (e.g., Data Distribution Service (DDS) for Real Time Systems,MER, etc.), one or more computer files (e.g., one or more data files,configuration files, library files, archive files, etc.), one or moresoftware components, or the like or any stack or other combinationthereof. Examples of system software include operating systems (e.g.,including one or more high-level operating systems, real-time operatingsystems, mobile operating systems, or the like or any combinationthereof), one or more kernels, one or more device drivers, firmware, oneor more utility programs (e.g., that help to analyze, configure,optimize, maintain, etc., one or more components of the electronicdevice), and the like.

Application software typically includes any application program thathelps users solve problems, perform tasks, render media content,retrieve (or access, present, traverse, query, create, organize, etc.)information or information resources on a network (e.g., the World WideWeb), a web server, a file system, a database, etc. Examples of softwarecomponents include device drivers, software CODECs, message queues ormailboxes, databases, etc. A software component can also include anyother data or parameter to be provided to application software, a webapplication, or the like or any combination thereof. Examples of datafiles include image files, text files, audio files, video files, hapticsignature files, and the like.

Also connected to the bus 100 is a user interface module 108. The userinterface module 108 is configured to facilitate user control of theelectronic device. Thus the user interface module 108 may becommunicatively coupled to one or more user input devices 110. A userinput device 110 can, for example, include a button, knob, touch screen,trackball, mouse, microphone (e.g., an electret microphone, a MEMSmicrophone, or the like or any combination thereof), an IR orultrasound-emitting stylus, an ultrasound emitter (e.g., to detect usergestures, etc.), one or more structured light emitters (e.g., to projectstructured IR light to detect user gestures, etc.), one or moreultrasonic transducers, or the like or any combination thereof.

The user interface module 108 may also be configured to indicate, to theuser, the effect of the user's control of the electronic device, or anyother information related to an operation being performed by theelectronic device or function otherwise supported by the electronicdevice. Thus the user interface module 108 may also be communicativelycoupled to one or more user output devices 112. A user output device 112can, for example, include a display (e.g., a liquid crystal display(LCD), a light emitting diode (LED) display, an active-matrix organiclight-emitting diode (AMOLED) display, an e-ink display, etc.), a light,an illumination source such as a flash or torch, a buzzer, a hapticactuator, a loud speaker, or the like or any combination thereof. In thecase of an iPhone 6, the flash includes a True Tone flash including adual-color or dual-temperature flash that has each color firing atvarying intensities based on a scene to make sure colors and skin tonestay true.

Generally, the user input devices 110 and user output devices 112 are anintegral part of the electronic device; however, in alternateembodiments, any user input device 110 (e.g., a microphone, etc.) oruser output device 112 (e.g., a loud speaker, haptic actuator, light,display, or printer) may be a physically separate device that iscommunicatively coupled to the electronic device (e.g., via acommunications module 114). A printer encompasses many different devicesfor applying our encoded signals to objects, such as 2D and 3D printers,etching, engraving, flexo-printing, offset printing, embossing, lasermarking, etc. The printer may also include a digital press such as HP'sindigo press. An encoded object may include, e.g., a consumer packagedproduct, a label, a sticker, a logo, a driver's license, a passport orother identification document, etc.

Although the user interface module 108 is illustrated as an individualcomponent, it will be appreciated that the user interface module 108 (orportions thereof) may be functionally integrated into one or more othercomponents of the electronic device (e.g., the CPU 102, the sensorinterface module 130, etc.).

Also connected to the bus 100 is an image signal processor 116 and agraphics processing unit (GPU) 118. The image signal processor (ISP) 116is configured to process imagery (including still-frame imagery, videoimagery, or the like or any combination thereof) captured by one or morecameras 120, or by any other image sensors, thereby generating imagedata. General functions typically performed by the ISP 116 can includeBayer transformation, demosaicing, noise reduction, image sharpening,filtering, or the like or any combination thereof. The GPU 118 can beconfigured to process the image data generated by the ISP 116, therebygenerating processed image data. General functions typically performedby the GPU 118 include compressing image data (e.g., into a JPEG format,an MPEG format, or the like or any combination thereof), creatinglighting effects, rendering 3D graphics, texture mapping, calculatinggeometric transformations (e.g., rotation, translation, etc.) intodifferent coordinate systems, etc. and send the compressed video data toother components of the electronic device (e.g., the volatile memory104) via bus 100. The GPU 118 may also be configured to perform one ormore video decompression or decoding processes. Image data generated bythe ISP 116 or processed image data generated by the GPU 118 may beaccessed by the user interface module 108, where it is converted intoone or more suitable signals that may be sent to a user output device112 such as a display, printer or speaker. GPU 118 may also beconfigured to serve one or more functions of a watermark detector. Insome cases GPU 118 searches for a watermark orientation component, whilepayload resolution is performed by the CPU 102.

Also coupled the bus 100 is an audio I/O module 122, which is configuredto encode, decode and route data to and from one or more microphone(s)124 (any of which may be considered a user input device 110) and loudspeaker(s) 126 (any of which may be considered a user output device110). For example, sound can be present within an ambient, auralenvironment (e.g., as one or more propagating sound waves) surroundingthe electronic device. A sample of such ambient sound can be obtained bysensing the propagating sound wave(s) using one or more microphones 124,and the microphone(s) 124 then convert the sensed sound into one or morecorresponding analog audio signals (typically, electrical signals),thereby capturing the sensed sound. The signal(s) generated by themicrophone(s) 124 can then be processed by the audio I/O module 122(e.g., to convert the analog audio signals into digital audio signals)and thereafter output the resultant digital audio signals (e.g., to anaudio digital signal processor (DSP) such as audio DSP 128, to anothermodule such as a song recognition module, a speech recognition module, avoice recognition module, etc., to the volatile memory 104, the storagememory 106, or the like or any combination thereof). The audio I/Omodule 122 can also receive digital audio signals from the audio DSP128, convert each received digital audio signal into one or morecorresponding analog audio signals and send the analog audio signals toone or more loudspeakers 126. In one embodiment, the audio I/O module122 includes two communication channels (e.g., so that the audio I/Omodule 122 can transmit generated audio data and receive audio datasimultaneously).

The audio DSP 128 performs various processing of digital audio signalsgenerated by the audio I/O module 122, such as compression,decompression, equalization, mixing of audio from different sources,etc., and thereafter output the processed digital audio signals (e.g.,to the audio I/O module 122, to another module such as a songrecognition module, a speech recognition module, a voice recognitionmodule, etc., to the volatile memory 104, the storage memory 106, or thelike or any combination thereof). Generally, the audio DSP 128 mayinclude one or more microprocessors, digital signal processors or othermicrocontrollers, programmable logic devices, or the like or anycombination thereof. The audio DSP 128 may also optionally include cacheor other local memory device (e.g., volatile memory, non-volatile memoryor a combination thereof), DMA channels, one or more input buffers, oneor more output buffers, and any other component facilitating thefunctions it supports (e.g., as described below). In one embodiment, theaudio DSP 128 includes a core processor (e.g., an ARM® AudioDE™processor, a Hexagon processor (e.g., QDSP6V5A)), as well as a datamemory, program memory, DMA channels, one or more input buffers, one ormore output buffers, etc. Although the audio I/O module 122 and theaudio DSP 128 are illustrated as separate components, it will beappreciated that the audio I/O module 122 and the audio DSP 128 can befunctionally integrated together. Further, it will be appreciated thatthe audio DSP 128 and other components such as the user interface module108 may be (at least partially) functionally integrated together.

The aforementioned communications module 114 includes circuitry,antennas, sensors, and any other suitable or desired technology thatfacilitates transmitting or receiving data (e.g., within a network)through one or more wired links (e.g., via Ethernet, USB, FireWire,etc.), or one or more wireless links (e.g., configured according to anystandard or otherwise desired or suitable wireless protocols ortechniques such as Bluetooth, Bluetooth Low Energy, WiFi, WiMAX, GSM,CDMA, EDGE, cellular 3G or LTE, Li-Fi (e.g., for IR- or visible-lightcommunication), sonic or ultrasonic communication, etc.), or the like orany combination thereof. In one embodiment, the communications module114 may include one or more microprocessors, digital signal processorsor other microcontrollers, programmable logic devices, or the like orany combination thereof. Optionally, the communications module 114includes cache or other local memory device (e.g., volatile memory,non-volatile memory or a combination thereof), DMA channels, one or moreinput buffers, one or more output buffers, or the like or anycombination thereof. In one embodiment, the communications module 114includes a baseband processor (e.g., that performs signal processing andimplements real-time radio transmission operations for the electronicdevice).

Also connected to the bus 100 is a sensor interface module 130communicatively coupled to one or more sensor(s) 132. Sensor 132 can,for example, include an accelerometer (e.g., for sensing acceleration,orientation, vibration, etc.), a magnetometer (e.g., for sensing thedirection of a magnetic field), a gyroscope (e.g., for trackingrotation, orientation, or twist), a barometer (e.g., for sensing airpressure, from which relative elevation can be determined), a windmeter, a moisture sensor, an ambient light sensor, an IR or UV sensor orother photodetector, a pressure sensor, a temperature sensor, anacoustic vector sensor (e.g., for sensing particle velocity), a galvanicskin response (GSR) sensor, an ultrasonic sensor, a location sensor(e.g., a GPS receiver module, etc.), a gas or other chemical sensor, orthe like or any combination thereof. Although separately illustrated inFIG. 5, any camera 120 or microphone 124 can also be considered a sensor132. Generally, a sensor 132 generates one or more signals (typically,electrical signals) in the presence of some sort of stimulus (e.g.,light, sound, moisture, gravitational field, magnetic field, electricfield, etc.), in response to a change in applied stimulus, or the likeor any combination thereof. In one embodiment, all sensors 132 coupledto the sensor interface module 130 are an integral part of theelectronic device; however, in alternate embodiments, one or more of thesensors may be physically separate devices communicatively coupled tothe electronic device (e.g., via the communications module 114). To theextent that any sensor 132 can function to sense user input, then suchsensor 132 can also be considered a user input device 110. The sensorinterface module 130 is configured to activate, deactivate or otherwisecontrol an operation (e.g., sampling rate, sampling range, etc.) of oneor more sensors 132 (e.g., in accordance with instructions storedinternally, or externally in volatile memory 104 or storage memory 106,ROM, etc., in accordance with commands issued by one or more componentssuch as the CPU 102, the user interface module 108, the audio DSP 128,the cue detection module 134, or the like or any combination thereof).In one embodiment, sensor interface module 130 can encode, decode,sample, filter or otherwise process signals generated by one or more ofthe sensors 132. In one example, the sensor interface module 130 canintegrate signals generated by multiple sensors 132 and optionallyprocess the integrated signal(s). Signals can be routed from the sensorinterface module 130 to one or more of the aforementioned components ofthe electronic device (e.g., via the bus 100). In another embodiment,however, any signal generated by a sensor 132 can be routed (e.g., tothe CPU 102), the before being processed.

Generally, the sensor interface module 130 may include one or moremicroprocessors, digital signal processors or other microcontrollers,programmable logic devices, or the like or any combination thereof. Thesensor interface module 130 may also optionally include cache or otherlocal memory device (e.g., volatile memory, non-volatile memory or acombination thereof), DMA channels, one or more input buffers, one ormore output buffers, and any other component facilitating the functionsit supports (e.g., as described above). In one embodiment, the sensorinterface module 130 may be provided as the “Sensor Core” (SensorsProcessor Subsystem (SPS)) from Qualcomm, the “frizz” from Megachips, orthe like or any combination thereof. Although the sensor interfacemodule 130 is illustrated as an individual component, it will beappreciated that the sensor interface module 130 (or portions thereof)may be functionally integrated into one or more other components (e.g.,the CPU 102, the communications module 114, the audio I/O module 122,the audio DSP 128, the cue detection module 134, or the like or anycombination thereof).

CONCLUDING REMARKS

Having described and illustrated the principles of the technology withreference to specific implementations, it will be recognized that thetechnology can be implemented in many other, different, forms. Toprovide a comprehensive disclosure without unduly lengthening thespecification, applicant hereby incorporates by reference each of theabove referenced patent documents in its entirety. Such documents areincorporated in their entireties, including all drawings and appendices,even if cited above in connection with specific of their teachings.These documents disclose technologies and teachings that can beincorporated into the arrangements detailed, and into which thetechnologies and teachings detailed herein can be incorporated.

The particular combinations of elements and features in theabove-detailed embodiments are exemplary only; the interchanging andsubstitution of these teachings with other teachings in this and theincorporated-by-reference patents are also contemplated. Manycombinations will be evident from the above disclosure.

1. An image processing method comprising: obtaining n images, where n isan integer greater than 2; using one or more multi-core processors,transforming each of the n images with digital watermarking, in whichthe digital watermarking includes a unique plural-bit payload for eachof the n images, in which said transforming yields watermarked n images;generating a composite interlaced image by interlacing the watermarked nimages; and attaching the composite interlaced image with a lenticularlens structure, said attaching yielding a lenticular image article. 2.The image processing method of claim 1 in which the lenticular lensstructure comprises a lens sheet or a set of extruded lens lines.
 3. Theimage processing method of claim 1 in which said transforming utilizesdifferent embedding strengths such that the composite interlaced imagecomprises multiple different signal strengths.
 4. The image processingmethod of claim 1 in which said lenticular lens structure reflects lightin a plurality of different directions.
 5. The image processing methodof claim 4 in which detection of the digital watermarking from thedifferent directions yields different signal strengths associated withthe digital watermarking.
 6. A lenticular image article producedaccording to the method of claim
 2. 7. A lenticular image articleproduced according to the method of claim
 5. 8. An apparatus comprising:memory storing: i) first optically captured image data corresponding toa first viewing angle relative to a lenticular image article, the firstoptically captured image data representing the lenticular image article,the lenticular image article comprising a composite interlaced image andlens structure, the composite interlaced image representing n interlacedimages, where n is an integer greater than 2, in which the n interlacedimages comprise digital watermarking, ii) second optically capturedimage data corresponding to a second viewing angle relative to alenticular image article, iii) third optically captured image datacorresponding to a third viewing angle relative to a lenticular imagearticle; means for processing the first optically captured image data,the second optically captured image data and the third opticallycaptured image data to decode the digital watermarking; and means fordetermining authenticity of the lenticular image article based on thedecoded digital watermarking.
 9. The apparatus of claim 8 in which thedigital watermarking includes a unique plural-bit payload for each ofthe n images.
 10. The apparatus of claim 9 in which said means fordetermining authenticity determines whether the unique plural-bitpayloads, or a subset of the unique plural-bit payloads, are recovered.11. The apparatus of claim 10 in which the digital watermarkingcomprises multiple different signal strengths.
 12. The apparatus ofclaim 11 in which said means for determining authenticity comprisesdetermining a combination of unique plural-bit payload reads anddifferent signal strengths.
 13. The apparatus of claim 11 in which saidmeans for determining authenticity comprises determining a signaturecomprising information corresponding to unique plural-bit payload readsand different signal strengths.
 14. A non-transitory computer readablemedium comprising instructions stored therein that, when executed by oneor more processors, cause the one or more processors to perform thefollowing: obtaining first optically captured image data correspondingto a printed object, the first optically captured image data beingcaptured under a first lighting condition, in which the printed objectcomprises a first ink printed thereon and a mixture of a second ink anda third ink printed thereon, the mixture of the second ink and the thirdink approximating the first ink, and in which an encoded signal iscarried on the printed object with the mixture of the second ink and thethird ink; obtaining second optically captured image data correspondingto the printed object, the second optically captured image data beingcaptured under smartphone flash illumination, in which a spectralresponse of the mixture of the second ink and the third ink has adifference compared to a spectral response of the first ink at awavelength where there occurs a spectral difference between the firstlighting condition and the smartphone flash illumination; determiningwhether the printed object is authentic based on encoded signaldetections from the first optically captured image data and the secondoptically captured image data.
 15. The non-transitory computer readablemedium of claim 14 in which said determining comprises determining thatthe printed object is authentic when the encoded signal is detectablefrom the second optically captured image data and is not detectable fromthe first optically captured image data.
 16. The non-transitory computerreadable medium of claim 14 in which the encoded signal comprisesdigital watermarking.
 17. The non-transitory computer readable medium ofclaim 14 in which the first ink comprises a metallic ink, and the secondink and the third ink each comprise a spot color.
 18. The non-transitorycomputer readable medium of claim 17 in which the first ink comprisesPANTONE 877 C, the second ink comprises PANTONE 804 C, and the third inkcomprises PANTONE Process Blue (PB) C.
 19. The non-transitory computerreadable medium of claim 18 in which the mixture of the second ink andthe third ink comprises 56% PANTONE 804 C and 44% PANTONE Process BlueC.
 20. The non-transitory computer readable medium of claim 14 in whichthe first lighting condition comprises D50 illumination, and in whichthe first lighting condition and the smartphone flash illuminationcomprise spectral differences at or around 480 nm and at or around 700nm.